Meghan Trainor stands out on the cover of Billboard‘s new series of covers.

The 20-year-old singer chatted about how “All About That Bass” came about. Check it

“I came to my session with producer Kevin Kadish with a list of titles, and immediately I was like, ‘Let’s do booty! And thickness! Like, it’s about the bass, not the treble,’ and he was into it. When you have a session, it’s like a blind date — you meet a stranger and make nice with them. He was telling me how he loved ’50s stuff, and I told him how I listened to Frank Sinatra before every session. He started making this beat to make it modern, and I started the first verse freestyle because I was like, ‘I rap.’ When a little white girl walks in and says, ‘I’m a rapper,’ they don’t actually want you to rap. But he was all about it.”

Meghan is also pictured at GREY NY’s Town Hall event on Thursday afternoon (December 11) where she gave a surprise performance to the 1,000+ employees of GREY NY, AdAge’s Advertising Agency of the Year, during their annual holiday meeting.

During the event, she was presented with a giant check from GREY for $10,000 to the Ryan Seacrest Foundation, a nonprofit dedicated to inspiring today’s youth through entertainment.